Heating block for an electric continuous flow heater and electric continuous flow heater

ABSTRACT

The invention is directed to a heating block ( 100 ) for a continuous flow heater in which a water flow system with channels is arranged in the heating block ( 100 ). A heating path ( 300 ) of the water flow system forms a hottest channel ( 340 ) with a hottest heating element ( 341 ) during operation of the continuous flow heater. The hottest channel ( 340 ) is arranged downstream of at least one channel ( 310, 320, 330 ) of the heating path ( 300 ) in a flow direction ( 110 ). The hottest channel ( 340 ) of the heating path ( 300 ) is surrounded by at least four channels which are located between an outer surface ( 120 ) of the heating block ( 100 ) and the hottest channel ( 340 ). Accordingly, the hottest channel ( 340 ) of the continuous flow heater is surrounded by at least four channels and is shielded relative to an air space ( 160 ).

RELATED APPLICATIONS

The present application claims priority to German Application No. 102016 002 942.0, filed on Mar. 11, 2016, the entirety of which isincorporated herein by reference.

BACKGROUND

Electric continuous flow heaters, in particular three-phase continuousflow heaters, having a heating block of plastic are known commercially.A water flow system comprising various channels which usually runparallel is arranged in the heating block. Advantageously, it is furtherknown to use bare wire heating bodies which are arranged in a heatingpath in the water flow system. The final heating body arranged in a flowdirection is the hottest as determined by function, since the waterwhich has already been preheated by the other heating bodies is suppliedto the final heating body viewed in flow direction and then heats thelatter to the desired target temperature. This hottest heating body atthe end of the heating path is the most prone to scaling.

SUMMARY

It is an object of the invention to prevent damage which can occur as aresult of scaling of the hottest heating body and to provide a heatingblock which is better protected against damage due to scaling.

An object of the invention may be met through the features of claim 1 orthrough the features of claim 3.

The hottest heating body which is located at the end of the heating pathviewed in flow direction is surrounded by other portions or channels ofthe water flow system, i.e., at least four other portions or channels ofthe water flow system are arranged around the hottest heating body.These at least four channels may be unheated sections of the water flowsystem or may also be heated sections of the water flow system.

In accordance with an embodiment of the invention, insulating trailingsections of the water flow system are arranged around the hottestheating body. These trailing sections are channels which are not heatedand through which flows the water heated by the heating bodies. Theunheated channels which serve as trailing sections and to electricallyinsulate the bare wire heating bodies located in the heating path are inthe immediate vicinity of the hottest heating body and downstream of thelatter viewed in flow direction.

Other heating channels are preferably arranged upstream of the hottestheating channel, and the hottest heating channel is connected downstreamof these other heating channels viewed in flow direction of the water.Therefore, it is preferred that the hottest heating channel issurrounded by the rest of the heating channels or at least by a heatingchannel arranged upstream thereof and the channels of the trailingsection.

The suggested heating block is preferably made of plastic, and thechannels located therein as heating path, leading section or trailingsection are arranged substantially in parallel in the heating body. Theindividual channels are connected to one another, respectively, in afoot piece and in a head piece so that the water flowing through thechannels is diverted in the head and in the foot and is guided from onechannel to the next channel.

The cold water flows through the heating body of the continuous flowheater initially through the channels which are arranged as leadingsections in the heating body. Subsequently, the water from the channelsof the leading section enter the channels of the heating path.

The channels, particularly the channels of the heating path, maypreferably have a round cross section. According to an embodiment of theinvention, the channels have at least partially an oval cross sectiondiverging from the round cross section or have a cross section with twoparallel sides joined by an arc. Accordingly, in a preferred embodiment,channels are suggested at least partially having a smaller width thanheight.

In the heating path, the water flows through the channels of the heatingpath either one after the other and/or preferably also at leastpartially in parallel. So-called parallel channels can be arrangedthereafter or therebetween, and the parallel channels are preferablylocated between two channels of the heating path and accordingly connecttwo or three channels of the heating path.

The hottest heating channel in flow direction of the water to be heatedpreferably lies at the end of the heating path so that the water in thehottest heating channel is hottest and the bare wire coil of the hottestheating channel is accordingly also hottest. Scaling is most likely tooccur at this hottest heating coil so that the water flow is reduced andthe hottest heating channel could overheat. In case of damage, thehottest heating channel is surrounded by other channels according to theinvention through which water preferably flows and/or no heating body isarranged so that the heating body remains tight overall even in case ofdamage in the hottest heating channel.

The hottest channel of the heating path is preferably surrounded by atleast four channels which are located between an outer surface of theheating block and the hottest channel. Accordingly, the hottest channelduring operation of the continuous flow heater is surrounded by at leastfour channels and is shielded from the air space.

According to an embodiment of the invention, the hottest channel isshielded from an outer surface by at least two unheated channels and atleast two heated channels.

A preferred heating block for a continuous flow heater has at least twochannels with one heating element in each instance. During operation ofthe continuous flow heater, the heating channel with the hottest heatingelement is hotter than the preceding heating element in flow direction.At least two unheated channels, as insulating leading section, arelocated upstream in flow direction of the channels with heating bodies.At least two channels are arranged as insulating trailing channelsdownstream of the heating channels in flow direction.

In a preferred embodiment, the hottest channel is surrounded by at leastfour channels so that the hottest channel is sealed relative to an airspace by the surrounding channels and remains sealed off in case of adefect in the hottest channel.

According to a preferred embodiment, the heating path comprises threechannels with a heating element in each instance and the hottest heatingchannel with a hottest heating element. The hottest heating channel islocated downstream of the three heating channels in flow direction.

The hottest channel is preferably surrounded in the heating block by atleast two channels and particularly by at least two, three or more thanthree unheated channels relative to an air space.

The channels are preferably arranged at least partially parallel to oneanother and parallel to the hottest channel.

The heating block is arranged in a housing of an electric continuousflow heater.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a perspective view a heating block with exposedcross-sections;

FIG. 2 shows a cross-sectional view of a heating block;

FIG. 3 shows a flow plan of the water flow system;

FIG. 4 shows electric connections of the heating body;

FIG. 5 shows a connection circuit board for the electric heating body;

FIG. 6 shows a star point bridge with connection of the heating body.

DETAILED DESCRIPTION

It will be appreciated by those ordinarily skilled in the art that theforegoing brief description and the following detailed description areexemplary (i.e., illustrative) and explanatory of the subject matter asset forth in the present disclosure, but are not intended to berestrictive thereof or limiting of the advantages that can be achievedby the present disclosure in various implementations.

It is noted that in this disclosure and particularly in the claimsand/or paragraphs, terms such as “comprises”, “comprised”, “comprising”and the like can have the meaning attributed to it in U.S. Patent law;e.g., they can mean “includes”, “included”, “including”, and the like.

FIG. 1 shows a heating block 100 with an inlet 104 and an outlet 105 ofan electric continuous flow heater. The heating block 100 is made ofplastic and has a head 101. A water flow system is located in theheating block. Viewed in a flow direction 110, the water flow systemcomprises a leading section 200, followed by heating path 300 and atrailing section 500 following the heating path 300.

The leading section 200 and the trailing section 500 are provided forelectric insulation relative to heating elements 311, 321, 331 and ahottest heating element 341 which are located in heating path 300. Theleading section 200 is divided into a quantity of channels. Accordingly,the leading section 200 is divided into unheated and insulating channels210, 220, 230, 240, 250.

Following the leading section 200 in flow direction 110 is the heatingpath 300, already mentioned, in which heating channels 310, 320, 330 anda hottest channel 340 are arranged in the embodiment example. A heatingelement 311, 321, 331 is arranged in a channel 310, 320, 330,respectively. The heating element 341 which is hottest during operationis arranged in the hottest channel 340. Therefore, during operation ofthe electric continuous flow heater 1, the hottest heating element 341in the hottest channel 340 is the hottest because the hottest heatingelement further heats the water which has already been preheated byheating elements 311, 321, 331 so that the hottest heating element 341is also the hottest in this case particularly at the end of the hottestchannel 340 in flow direction 110.

Further, a flow unit 140 and an adjusting valve 130 are arranged at theheating block. The adjusting valve is preferably arranged in the leadingsection 200, where the flow unit 140 is also arranged.

The heating block 100 is shown in section in FIG. 2. The hottest heatingbody 341 which is arranged in the hottest channel 340 is surrounded byseven channels in the embodiment example. The seven channels seal offthe hottest heating body 341 from an air space 160 and, accordingly, thehottest channel 340 is also shielded from, or at a distance from, anouter surface 120 of the heating block 100.

In the embodiment example, the hottest channel 340 is surrounded bythree channels 310, 320, 330 which are heated. Further, the hottestchannel 340 is surrounded by two parallel channels 410 and 420 in whichthe water coming from channel 320 and 330 is guided to the hottestchannel 340 during operation of the continuous flow heater. The twoparallel channels 410 and 420 serve to guide the already preheated waterto the start of the hottest channel 340 during operation of thecontinuous flow heater 1. The deflection of the already preheated watertakes place, seen in flow direction 110, downstream of the unheatedparallel channels 410 and 420 in a foot 102 as is shown schematically inFIG. 3.

In the embodiment example shown in FIG. 4, the electrical connection ofheating elements 311, 321 and 331 and of the hottest heating element 341is carried out by a printed circuit board 600. In this embodiment, theprinted circuit board 600 has a finger 601, 602, 603, 604 for connectingeach heating element 311, 321 and 331 and the hottest element 341. Thesefingers 601, 602, 603, 604 are component parts of the printed circuitboard 600, and conductor paths which are provided for the flow ofelectric current to heating elements 311, 321 and 331 and to the hottestelement 341 are located on the fingers. In an embodiment, the printedcircuit board 600 is arranged in head 101 in the area of the adjustingvalve 130. The hottest channel 340 and the hottest heating element 341are supplied with power via finger 604.

Heating elements 311, 321, 331 and the hottest heating element 341 areguided or stretch from head 101 to foot 102, and a star point bridge 103by which the heating coils are electrically connected and accordinglyarranged in a so-called electric star point as is shown in FIG. 6 isarranged in the area of the foot 102.

The trailing section 500 is divided into a plurality of channels 510,520, 530 which are arranged in series one after the other.

Fingers 601, 602, 603, 604 of the heating body connection printedcircuit board 600 are preferably configured to be resilient so that atolerance compensation is achieved with respect to heating bodyconnection pins of the heating bodies, preferably in head 101. Theheating body connection pins can be located at different heights in thehead 101 as a result of assembly tolerances and/or compressive stressesin the water. The printed circuit board 600 other serves to protectagainst wiring errors because only one assembling direction is possibleand correct.

The printed circuit board 600, as “break-off circuit,” is preferably acomponent part of a main printed circuit board. The printed circuitboard 600 is attached to the main printed circuit board, preferably at apredetermined breaking line.

The main circuit board is preferably manufactured together with theprinted circuit board 600. This is preferably carried out in THTmounting and/or SMD mounting, and electronic components are connected bya solder wave to conductor paths of the printed circuit board 600 andmain circuit board. During the production of the continuous flow heater,the printed circuit board 600 is broken off from the main circuit boardand arranged at head 101.

While this invention has been described in conjunction with the specificembodiments outlined above, it is evident that many alternatives,modifications, and variations will be apparent to those ordinarilyskilled in the art. Accordingly, the preferred embodiments of theinvention as set forth above are intended to be illustrative, notlimiting. Various changes may be made without departing from the spiritand scope of the inventions as defined in the following claims.

1. Heating block for a continuous flow heater comprising: a water flowsystem, wherein the water flow system is arranged in the heating block,and has a heating path, a channel of the heating path being the hottestduring operation, wherein a hottest heating element is arranged in thehottest channel, and the hottest channel is arranged downstream of atleast one channel of the heating path in a flow direction, wherein thehottest channel of the heating path is surrounded by at least fourchannels which are located between an outer surface of the heating blockand the hottest channel so that the channel which is hottest duringoperation of the continuous flow heater is surrounded by at least fourchannels and is shielded relative to an air space.
 2. Heating blockaccording to claim 1, wherein the hottest channel is surrounded by atleast two channels which are unheated, and the hottest channel issurrounded by at least two further channels of the heating path so thatthe hottest channel is shielded relative to an outer surface by at leasttwo unheated channels and by at least two heated channels.
 3. Heatingblock for a continuous flow heater comprising: at least two channelshaving a heating element in each instance, wherein the heating channelwith the heating element is hotter than heating elements duringoperation of the continuous flow heater, wherein at least two unheatedchannels as insulating leading section are located upstream of channelswith heating bodies in a flow direction, and at least two channels asinsulating trailing channels are arranged downstream of heating channelsin the flow direction, wherein the hottest channel is surrounded by atleast four channels so that the hottest channel is sealed relative to,and sealed off from, an air space by the surrounding channels in case ofa defect in the hottest channel.
 4. Heating block according to claim 3,wherein the heating path is formed of three channels with a heatingelement and the hottest heating channel, and wherein the hottest channelis located downstream of the three channels viewed in flow direction. 5.Heating block according to claim
 4. wherein the hottest channel issurrounded in the heating block by at least two channels andparticularly at least two, three or more than three unheated channelsrelative to an air space.
 6. Heating block according to claim 5, whereinthe channels are arranged at least partially parallel to one another andparallel to the hottest channel.
 7. Electric continuous flow heater witha heating block according to claim 3.